Improved subaqueous foundation



panying drawings, and to the letters of reference marked thereon.

JAMES B..EADS, OF ST.*LOUIS, MISSOURI..

Letters-Patent No. 78,793, dated June 9, 1868.

IMrnovsD SUBAQUEOUS FOUNDATIQN, i

@In rlgaul rifatta tu in g'te trttas man ma mutxigfpzvt at tip aina.

To ALL WHoM 1r MAY coNcEaNQ l Be it known that I, JAMES B. EADS,of thecity of St. Louis,in the county of St. Louis, and State 'of i Missouri,have made certain new and useful Improvements in LConstructingSubaqueousFoundations; ,andjI do hereby declare that the following 'is a full andclear description thereof, reference being had to the m- Itis well knownthat in the construction of bridge-piers, dams, breakwaters, and similarstructuresthe foundations are made yupon the firm subaqueousv strata ofrock or hard soil. Toconstruct said structures `firmly 4 upon the propersubstrato., various general methods have been devised. In the methodused by Brunel at the Saltash bridge, and by Keller at the Kehl-Rhinebridge, a strong box was employed', the said box being open" at thebottom, and sustaining the masonry on its top, when supported by chains.The masonry was laid abo-vc water, the foundation-box being loweredasthe masonry was raisedr When the box reached the watcrbed, it becamenecessary to excavate the sand or other subsoil to permit the box todescend and reachV the iirrnsubstratum intended to support thestructure. To enable workmen to perform the work of excavation undersaid box, compressed air was lforced into the same, thus forcing out thewater therein, and supplying a medium` for respiration for thelaborers.4 It will be seen that in said method the supply of compressedair, and its retention,

necessitate various and 4complex devices, which, at the same time, aremodified by the necessities for passage of workmen and material from theplatform above to-tlie work-site below. And-it isfurther apparentthattheV progress of said work must be slow, because ofthe limited spacea'orded to apply the powers of laborers, and the circumstantialoperations which must be performed to achieve limited results. Theadvantage possessed by said general method is in the possibility oflaying all masonry above water, but the disadvantage in said method isin the delay and expense caused by the manner of excavating thesubaqueous passage for lthe descent ofv the foundation-boxer crib. Toretain the general: advantage of said method, and to evade its saiddefects, the nature of my improved method ofconstructing subaqueousfoundations is in the prior formation of thc' passage in which the Apieror other structure descends as it is constructed, and for saidpurposethc nature of'` my invention is in the application of anopenfended tube or caisson, which shall rstbe sunk surrounding thepier-site, and from within which the sand or light subsoil shall havebeen excavated, thereby forming-within said caisson a clear sitecontaining no other obstruction but water to 'ithe'dcscent of the innerstructure. "There-' upon the masonry is constructed in a suitablecaisson, sectional or otherwise in its detail constructiomor Vsaid imasonry inlay be built upon a simple platform, and the said caisson orplatform and superinrcumbent 'masonry being sustained either by thewater-displacement or by screws and chains, and being guided properly inits' descent as the masonry is built up.

To enable those skilled herein to use my said improvement, I will nowdescribe the same in its generalv detail constructions and operations,referring herein tothe accompanying Figure lqas a horizontal sectionalplan, and to Y Figure 2 as a vertical sectional elevation. a V In saidiignres similar letters of reference are used-to indicate similar parts.

I- construct the enclosing caisson A of wood or iron, and sink the same,to reach the iirm substratum, asl

indicated in iig. 2. To facilitate the descent of said caisson, thelower edge a iscurved outwardly,and may be' sharpened or shod. Inlowering the caisson A, the weight thereof, with any added ballastthatmay he needed,

-will be aided by the excavation of the sand, gravel, or light subsoil`within the caisson; said sand, gravehor,

subsoil being `excavated by dredges or sand-pumps, or similar devices.By said processes the space within the' caisson A willbe cleared of allobstructions except water, and, as the water-levels withii and withoutthe -sme are or may be properly adjusted, the compressionupon thecaisson itselfwill be so slight that a light andinia-X#V pensiveconstruction thereof is admissible.

I construct, furthermore, a platform, B, to sustain thc masonry,andguide said platform B bythe guide-v posts B arranged on the innersurface of the caisson A.' In case the weight of themasonry built on Bcannot beprolperly balanced by the upward pressure of the water' in A,suitable valves may be arranged to add a bal.

last o'n Water on B, as required. Around the platform B, I arrange thecaisson Gf' enclosing the masonry.l Inv the construction of C, it isadvisableto arrange the same in sections Cl CZ C3, the said sectionsbeing added successively as the building of the masonry 'withinprogresses, and the platform B and caisson C descend.V

It will be seen that, byl the caisson C, the water may be excluded fromthe masonry until the same is set,

'and that the sides of `*said caisson maybe braced by proper bracesacting against the masonry within the same,

and thus the caisson be relieved to a great extent of the p'rcssureofthe surrounding water, thereby permitting a light and inexpensiveconstruction ofsaid caisson. Y, V

j When the platform B has been lowered to the subsoil prepared byblasting, or by layers of beton to receive the same properly, it willvbeeasyto remove the enclosing sectional caisson C by disconnectin` thesame or'its separate sections from each other nndfrom the platform B.The outer caisson A may then be removed, and the removal hereof will befacilitated by a construction thereof in sect-ions similarly to thecaisson C.

Having thus fully described myinvention, what I claim is iThecombination and arrangement of the outer caisson, its ribs or posts BB', with the internal caisson, C, in th'e'manner and for thepurposesubstantially as herein set forth.

'JA's B. EAbs. s Witnesses:

Gro. P. HERTHEL, Jr., GEO. W. HERBERT.

